Assessment Assessment of fetal of fetal

wellbeingwellbeing

ByBy

Dr. Khattab KAEODr. Khattab KAEO

Prof. of Obstetrics and Gynaecology Prof. of Obstetrics and Gynaecology Faculty of Medicine, Al-Azhar University, Faculty of Medicine, Al-Azhar University,

DamiettaDamietta

Indications for fetal wellbeing surveillance

Many cases of medical Many cases of medical disorders. disorders.

Prolonged pregnancy: Prolonged pregnancy: >10 days after the >10 days after the EDD or earlier in older EDD or earlier in older mothers. mothers.

Reduced fetal Reduced fetal movements. movements.

Cardiff count-to-ten: Cardiff count-to-ten: The patient begins to count movements at The patient begins to count movements at

8 AM daily and marks the 1/2 h at which 8 AM daily and marks the 1/2 h at which the 10th movement is felt. the 10th movement is felt.

If 10 movements are not felt by 8 PM orIf 10 movements are not felt by 8 PM orif it takes twice to feel 10 movements as if it takes twice to feel 10 movements as

on prior days, the physician is noted. on prior days, the physician is noted. In another opinion, notification is indicated In another opinion, notification is indicated

if there is no movement for 1 day orif there is no movement for 1 day orif <10 movements are felt on 2 days. if <10 movements are felt on 2 days.

Cases with reduced fetal movements are Cases with reduced fetal movements are referred for CTG tracing.referred for CTG tracing.

Symphysis-fundal height (SFH):Symphysis-fundal height (SFH): Using a non-stretchable tape, the Using a non-stretchable tape, the

fundal height is measured from the fundal height is measured from the upper border of the symphysis upper border of the symphysis

pubis.pubis. From the 24th week of gestation From the 24th week of gestation

this measurement follows "the rule this measurement follows "the rule of thumb" i.e. the fundal height in of thumb" i.e. the fundal height in centimetres (cm) corresponds to centimetres (cm) corresponds to

gestational age in weeks. In a gestational age in weeks. In a normally-progressing pregnancy normally-progressing pregnancy

SFH measures 30 cm at 30 weeks, SFH measures 30 cm at 30 weeks, 34 cm at 34 weeks.... 34 cm at 34 weeks....

Biophysical profile (BPP):Biophysical profile (BPP): Constituents:Constituents:

--3 gross FMs in 30 min. 3 gross FMs in 30 min. Simultaneous limb and trunk Simultaneous limb and trunk movements are counted as a movements are counted as a single movement. single movement.

- Fetal tone is exemplified by - Fetal tone is exemplified by prompt prompt returnreturn to flexion after to flexion after extension of the limbs or trunk. extension of the limbs or trunk. Other examples include arching, Other examples include arching, kicking and opening and closing kicking and opening and closing of the hands. of the hands.

-Continuous breathing movements -Continuous breathing movements (movement of chest & abdominal (movement of chest & abdominal wall) for wall) for 30 seconds at least 30 seconds at least once in 30 min. once in 30 min.

Principles: - If the normal NST findings are not obtained within 20 min, test time is extended to 40 min. - Due to fetal cycles of activity-inactivity (20-40 min), it is advisable to have a meal 1-2 hours before testing. - Frequency of testing depends on the clinical situation and varies from daily to weekly testing. - BPP is useful from 28 weeks onwards. The earliest we begin testing is at 26 weeks. - The principle is that different sites in the fetal brain control different biophysical events. FMs, fetal tone, FBMs & CTG are markers of acute fetal asphyxia, while amniotic fluid volume is a marker of chronic hypoxia. - The first marks to go in case of fetal hypoxia are breathing and FHR reactivity, and the last to go are movements and tone.

Interpretation:Interpretation: Each parameter scores either 2 or 0. Each parameter scores either 2 or 0.

- With a score of 8-10 intervention is not indicated, un less - With a score of 8-10 intervention is not indicated, un less for clinical reasons & the test is repeated weeklyfor clinical reasons & the test is repeated weekly

- A score of 6 is equivocal. Intervention is advised if the - A score of 6 is equivocal. Intervention is advised if the fetus is mature; if not, re-test within 24 h. fetus is mature; if not, re-test within 24 h.

- With a score of <6 the relative risk of fetal or NN death is - With a score of <6 the relative risk of fetal or NN death is increased by 6-x. A score of <6 could be reassuring increased by 6-x. A score of <6 could be reassuring provided there is no oligohydramnios. provided there is no oligohydramnios.

- A score of 4 is associated with a PNMR of 90/1000. - A score of 4 is associated with a PNMR of 90/1000.

- A score of <4 in a mature fetus is an indication of - A score of <4 in a mature fetus is an indication of immediate delivery. If the fetus is immature, this immediate delivery. If the fetus is immature, this constitutes a real dilemma. The decision could be constitutes a real dilemma. The decision could be immediate delivery, delivery preceded by steroid-immediate delivery, delivery preceded by steroid-induced lung maturation, or further fetal assessment by induced lung maturation, or further fetal assessment by prolonged NST or CST depending on the clinical prolonged NST or CST depending on the clinical situation and the degree of fetal immaturity. situation and the degree of fetal immaturity.

- The incidence of false -ve rate = 0.8/1000 i.e. - The incidence of false -ve rate = 0.8/1000 i.e. the test has a high predictive value –within a the test has a high predictive value –within a week- for good perinatal outcome when the week- for good perinatal outcome when the result is normal. In contrary, the false +ve rate result is normal. In contrary, the false +ve rate for abnormal NST or abnormal FBMs is >80% for for abnormal NST or abnormal FBMs is >80% for poor perinatal outcome and >95% for PND. BPP poor perinatal outcome and >95% for PND. BPP is affected by factors which suppress the CNS is affected by factors which suppress the CNS such as hypoxia, infection & medication. such as hypoxia, infection & medication.

- -With an abnormal score, the possibility of With an abnormal score, the possibility of neurological dysfunction should be consideredneurological dysfunction should be considered . .

- The test is time-consuming and provides little - The test is time-consuming and provides little additional information. It has now been super-additional information. It has now been super-seded by CTG&amniotic fluid vol (modified BPP) seded by CTG&amniotic fluid vol (modified BPP) and growth assessment. and growth assessment. - In modern evidence-based obstetrics BPP has - In modern evidence-based obstetrics BPP has been classified as care of unknown been classified as care of unknown effectivenesseffectiveness

Cardiotocography (CTG)Cardiotocography (CTG)Scaling is recommended at 3 cm/min paper speed. Scaling is recommended at 3 cm/min paper speed. Definitions:Definitions: Baseline FHR:Baseline FHR: 110-150 bpm according to the 110-150 bpm according to the

FIGO classification. It is the modal characteristics that FIGO classification. It is the modal characteristics that prevail apart from periodic accelerations or de-prevail apart from periodic accelerations or de-celerations. It decreases 24 bpm between 16 weeks celerations. It decreases 24 bpm between 16 weeks and term (and term (1bpm/w) due to maturation of vagal tone 1bpm/w) due to maturation of vagal tone Rate is rounded to increments of 5 bpm during a 10-min Rate is rounded to increments of 5 bpm during a 10-min segment. The minimum interpretable baseline duration segment. The minimum interpretable baseline duration must be 2 min. must be 2 min.

Long-term variabilityLong-term variability is oscillatory changes is oscillatory changes that occur over 1 min; that occur over 1 min; 55-25 bpm. It may be reduced for -25 bpm. It may be reduced for up to 30 min (or even absent) due to fetal sleep or up to 30 min (or even absent) due to fetal sleep or drugs (diazepam). However, the most important cause drugs (diazepam). However, the most important cause is fetal hypoxia. Variability is regulated by the is fetal hypoxia. Variability is regulated by the sinoaortal node. sinoaortal node.

Short-term variabilityShort-term variability is taken from 1 beat [or is taken from 1 beat [or R wave] to the next, so it is most reliably deter-mined R wave] to the next, so it is most reliably deter-mined with a scalp electrode.with a scalp electrode.

Reduced variability is the most reliable sign of fetal Reduced variability is the most reliable sign of fetal compromise. compromise.

Bradycardia:Bradycardia: <100 bpm for <100 bpm for >3 min (according to FIGO; >3 min (according to FIGO;

<110 bpm according to <110 bpm according to ACOG). It could be due to ACOG). It could be due to drugs (like drugs (like -blockers) or -blockers) or

congenital fetal heart block. congenital fetal heart block. However, it could be due to However, it could be due to

fetal distress. fetal distress.

Tachycardia:Tachycardia: >150 bpm (according to FIGO; >150 bpm (according to FIGO; >160 bpm according to ACOG). It could be >160 bpm according to ACOG). It could be idiopathic, or due to drugs (like atropine & idiopathic, or due to drugs (like atropine & mimetics), fever, maternal or fetal mimetics), fever, maternal or fetal hyperthyroid., maternal or fetal anaemia or hyperthyroid., maternal or fetal anaemia or prematurity. However, it could be due to prematurity. However, it could be due to fetal distress. fetal distress. Sinusoidal pattern:Sinusoidal pattern: Type I (saw tooth) with Type I (saw tooth) with almost fixed variability. It is almost fixed variability. It is benignbenign

Type II with smooth sine wave & a Type II with smooth sine wave & a regular frequency of <6 cycles/min and an regular frequency of <6 cycles/min and an amplitude of amplitude of >>10 bpm. It is pre-terminal. It 10 bpm. It is pre-terminal. It is seen with serious fetal anemia of D-iso-is seen with serious fetal anemia of D-iso-immunisation, ruptured vasa previa & twin-immunisation, ruptured vasa previa & twin-to-twin transfusion. Differential diagnosis is to-twin transfusion. Differential diagnosis is effect of drugs like morphineeffect of drugs like morphine, alphaprodine , alphaprodine and butorphanoland butorphanol

DecelerationDecelerationGradual fall in FHR by ≥15 bpm for ≥15 Gradual fall in FHR by ≥15 bpm for ≥15

sec. It is stimulated by sec. It is stimulated by chemoreceptors. chemoreceptors.

Early deceleration:Early deceleration: The nadir occurs ≤20 The nadir occurs ≤20 sec of the peak of contractionsec of the peak of contraction; now: ; now: 30 sec after the onset of contraction30 sec after the onset of contraction). ). The waveform is symmetrical. Early The waveform is symmetrical. Early deceleration is the result of head deceleration is the result of head compression during uterine contrac. compression during uterine contrac. which probably causes vagal nerve which probably causes vagal nerve activation. It is not associated with activation. It is not associated with hypoxia, acidemia or low Apgar scores. hypoxia, acidemia or low Apgar scores.

This early deceleration is deemed benign because some contractions are not associatedThis early deceleration is deemed benign because some contractions are not associated with with decelera tion, and shoulders (particularly pre-deceleration ones) are not lost. Finally, other items like decelera tion, and shoulders (particularly pre-deceleration ones) are not lost. Finally, other items like baseline FHR and variability are normal. The most right drop in FHR (white arrow) is not regarded as baseline FHR and variability are normal. The most right drop in FHR (white arrow) is not regarded as decelera-tion because the drop is <15 bpm. decelera-tion because the drop is <15 bpm.

Early decelerations are not always benign.Early decelerations are not always benign.It is deemed sinister in the following conditions:It is deemed sinister in the following conditions:

1- 1- If associated with one of theIf associated with one of the following: following: FHR <100 bpm FHR <100 bpm ineffective placental perf ineffective placental perf

Rising FHR. Rising FHR. Loss of long-term variability. Loss of long-term variability. Loss of shouldering. Loss of shouldering.

2-2- If unprovoked i.e. without active uterine contractions. If unprovoked i.e. without active uterine contractions.

3-3- If it is repetitive or deep. If it is repetitive or deep.

Late decelerationLate decelerationThe waveform of FHR decrease shows gradual onset The waveform of FHR decrease shows gradual onset

and recovery and is symmetrical. Onset begins at or and recovery and is symmetrical. Onset begins at or after the peak of contraction. The nadir occurs >20 after the peak of contraction. The nadir occurs >20 sec after the peak of contraction sec after the peak of contraction (now: (now: 30 sec)30 sec)..

Return to the baseline only occurs after the Return to the baseline only occurs after the contractioncontraction has ended. This diagnosis is applicable only for has ended. This diagnosis is applicable only for 3 3 such decelerations following such decelerations following consecutiveconsecutive contractionscontractions So, it can occur occasionally (reassuring signs are: So, it can occur occasionally (reassuring signs are: the presence of shouldering & variability, in addition the presence of shouldering & variability, in addition to normal baseline). Typically, depth is no >10-20 to normal baseline). Typically, depth is no >10-20 bpm (i.e. shallow). It is attributable to reduced bpm (i.e. shallow). It is attributable to reduced placental blood flow with deep ones are seen with placental blood flow with deep ones are seen with abruption. It more commonly occurs with maternal abruption. It more commonly occurs with maternal hypotension and excessive uterine activity. It is hypotension and excessive uterine activity. It is deemed sinister if deep (FHR decreases by>60 bpm) deemed sinister if deep (FHR decreases by>60 bpm) and prolonged (persists for >60 sec). and prolonged (persists for >60 sec).

Early and late decelerations almost reflect the shape of Early and late decelerations almost reflect the shape of uterine contraction and all dips are of almost uterine contraction and all dips are of almost identical shape. identical shape.

Variable decelerationsVariable decelerations All decelerations that are not early or late. All decelerations that are not early or late.

These are the most common decelerations. These are the most common decelerations. Dips are of variable shape, depth and Dips are of variable shape, depth and correlation to uterine contractions. Onset is correlation to uterine contractions. Onset is abrupt and nadir follows after a <30 sec abrupt and nadir follows after a <30 sec period. Duration is <2 min. Variable de-period. Duration is <2 min. Variable de-celeration is attributable to compression of celeration is attributable to compression of the umbilical cord. It indicates fetal distress if the umbilical cord. It indicates fetal distress if deep (<70bpm[deep (<70bpm[signif variable decelerationsignif variable deceleration) ) and persistent (lasting for 60 sec with each and persistent (lasting for 60 sec with each contraction) or associated with reduced contraction) or associated with reduced variability or meconium-stained liquor. variability or meconium-stained liquor.

AccelerationsAccelerations

These are abrupt increase in FHR (>15 These are abrupt increase in FHR (>15 bpm) in response to fetal movement, bpm) in response to fetal movement, uterine contractions, cord occlusion or uterine contractions, cord occlusion or fetal acoustic stimulation, stimulation fetal acoustic stimulation, stimulation during pelvic examination or scalp blood during pelvic examination or scalp blood sampling. During labour they are nearly sampling. During labour they are nearly always associated with fetal movement. always associated with fetal movement. They are always reassuring and almost They are always reassuring and almost always confirm absence of acidemia. always confirm absence of acidemia.

FIGO definition of antenatal CTGFIGO definition of antenatal CTG

Normal:Normal: baseline of 110-150 bpm, baseline of 110-150 bpm, variability of 5-25 bpm, ≥2 variability of 5-25 bpm, ≥2 accelerations in 20 min and absence accelerations in 20 min and absence of deceleration except for mild ones of deceleration except for mild ones of very short duration. of very short duration.

Suspicious:Suspicious: baseline 100-110 or 150-170 baseline 100-110 or 150-170 bpm, variability of 5-10 bpm for >40 min bpm, variability of 5-10 bpm for >40 min or >25 bpm, no accelerations for >40 min or >25 bpm, no accelerations for >40 min and sporadic deceleration of any type and sporadic deceleration of any type unless severe. unless severe.

Pathological:Pathological: baseline of <100 or >170 baseline of <100 or >170 bpm, variability of <5 bpm, recurring and bpm, variability of <5 bpm, recurring and repeated decelerations of any type. repeated decelerations of any type.

Limitations of CTG useLimitations of CTG use The major limitation of CTG is that The major limitation of CTG is that fetalfetal adaptationadaptation results in results in maintenance of the FHR until death. An acute reduction in Omaintenance of the FHR until death. An acute reduction in O22 delivery produces a transient delivery produces a transient bradycardiabradycardia. However, if reduction . However, if reduction in Oin O22 delivery is prolonged, the FHR returns to normal (a delivery is prolonged, the FHR returns to normal (a possible effect of catechol.), but with a further acute reduction possible effect of catechol.), but with a further acute reduction in Oin O22 delivery there will be lack of response (no reaction). In delivery there will be lack of response (no reaction). In progressing utero-placental insufficiency there would be: loss progressing utero-placental insufficiency there would be: loss of acceleration of acceleration deceleration deceleration progressive reduction in progressive reduction in variability. The rate usually remains normal. variability. The rate usually remains normal. Also, Also, fetal quiescence fetal quiescence is normally associated with loss of is normally associated with loss of acceleration and low variability. A non-reactive CTG with acceleration and low variability. A non-reactive CTG with variability present should be continued (up to 2 h) until fetal variability present should be continued (up to 2 h) until fetal activity occurs or until its continued absence indicates a activity occurs or until its continued absence indicates a problem. problem. FHR tracingFHR tracing 15% false +ve rate & 0.3% false -ve rate In 15% false +ve rate & 0.3% false -ve rate In another opinion 40% of abnormal CTGs occurs in the absence another opinion 40% of abnormal CTGs occurs in the absence of fetal hypoxia; CS rate will be trebled if CTGs are used alone. of fetal hypoxia; CS rate will be trebled if CTGs are used alone. Even with the most severely abnormal CTG, the fetus will be Even with the most severely abnormal CTG, the fetus will be hypoxic in only half the cases. hypoxic in only half the cases. Normal CTG is insufficiently reassuring in at-risk cases.Normal CTG is insufficiently reassuring in at-risk cases.

Non-stress test (NST)Non-stress test (NST) The test correlates FHR response to fetal The test correlates FHR response to fetal movements. If no fetal movement felt within movements. If no fetal movement felt within 20 min, the test is extended for 20 min more, 20 min, the test is extended for 20 min more, perhaps after acoustic stimulation. perhaps after acoustic stimulation. The woman is put in the semi-Fowler position The woman is put in the semi-Fowler position with a lateral tilt. with a lateral tilt. Two accelerations (↑ in FHR by Two accelerations (↑ in FHR by >>15 bpm for 15 bpm for >>15 sec) within 20 min = "reactive". If this is 15 sec) within 20 min = "reactive". If this is not achieved within 20 min, the test is deemed not achieved within 20 min, the test is deemed "non-reactive". The incidence of false positive "non-reactive". The incidence of false positive rate = 3/1000. The incidence of false negative rate = 3/1000. The incidence of false negative rate = 3/1000. rate = 3/1000. Absence of acceleration may indicate hypoxia. Absence of acceleration may indicate hypoxia. Deceleration with Braxton-Hicks contractions Deceleration with Braxton-Hicks contractions (unstress test) indicates oxygen insufficiency (unstress test) indicates oxygen insufficiency and requires urgent investigation. and requires urgent investigation.

Contraction stress test (CST)Contraction stress test (CST) The test time is 90 min. The test time is 90 min. Uterine contractions are induced and maintained at Uterine contractions are induced and maintained at a rate of 3/10 min. a rate of 3/10 min. The test is deemed "positive" if there are persistent The test is deemed "positive" if there are persistent late decelerations with >50% of the contractions. late decelerations with >50% of the contractions. "equivocal" if late de-celerations are occasional. "equivocal" if late de-celerations are occasional. "negative" if there is no late deceleration. "negative" if there is no late deceleration. The incidence of false negative rate =1/1000The incidence of false negative rate =1/1000If negative, the test is repeated weekly. If positive, If negative, the test is repeated weekly. If positive, a complete BPP is recommended. a complete BPP is recommended. The test is contraindicated if there is a previous The test is contraindicated if there is a previous uterine scar or threatened preterm labour. uterine scar or threatened preterm labour.

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